Index: cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
===================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
+++ cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
@@ -364,8 +364,6 @@
 /// Objective-C parser diagnostics
 def err_expected_minus_or_plus : Error<
   "method type specifier must start with '-' or '+'">;
-def err_objc_no_attributes_on_category : Error<
-  "attributes may not be specified on a category">;
 def err_objc_missing_end : Error<"missing '@end'">;
 def note_objc_container_start : Note<
   "%select{class|protocol|category|class extension|implementation"
Index: cfe/trunk/include/clang/Sema/Sema.h
===================================================================
--- cfe/trunk/include/clang/Sema/Sema.h
+++ cfe/trunk/include/clang/Sema/Sema.h
@@ -7666,7 +7666,8 @@
                                     Decl * const *ProtoRefs,
                                     unsigned NumProtoRefs,
                                     const SourceLocation *ProtoLocs,
-                                    SourceLocation EndProtoLoc);
+                                    SourceLocation EndProtoLoc,
+                                    AttributeList *AttrList);
 
   Decl *ActOnStartClassImplementation(
                     SourceLocation AtClassImplLoc,
Index: cfe/trunk/lib/Parse/ParseObjc.cpp
===================================================================
--- cfe/trunk/lib/Parse/ParseObjc.cpp
+++ cfe/trunk/lib/Parse/ParseObjc.cpp
@@ -278,11 +278,6 @@
     T.consumeClose();
     if (T.getCloseLocation().isInvalid())
       return nullptr;
-
-    if (!attrs.empty()) { // categories don't support attributes.
-      Diag(nameLoc, diag::err_objc_no_attributes_on_category);
-      attrs.clear();
-    }
     
     // Next, we need to check for any protocol references.
     assert(LAngleLoc.isInvalid() && "Cannot have already parsed protocols");
@@ -294,16 +289,11 @@
                                     /*consumeLastToken=*/true))
       return nullptr;
 
-    Decl *CategoryType =
-    Actions.ActOnStartCategoryInterface(AtLoc,
-                                        nameId, nameLoc,
-                                        typeParameterList,
-                                        categoryId, categoryLoc,
-                                        ProtocolRefs.data(),
-                                        ProtocolRefs.size(),
-                                        ProtocolLocs.data(),
-                                        EndProtoLoc);
-    
+    Decl *CategoryType = Actions.ActOnStartCategoryInterface(
+        AtLoc, nameId, nameLoc, typeParameterList, categoryId, categoryLoc,
+        ProtocolRefs.data(), ProtocolRefs.size(), ProtocolLocs.data(),
+        EndProtoLoc, attrs.getList());
+
     if (Tok.is(tok::l_brace))
       ParseObjCClassInstanceVariables(CategoryType, tok::objc_private, AtLoc);
       
Index: cfe/trunk/lib/Sema/SemaDeclObjC.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaDeclObjC.cpp
+++ cfe/trunk/lib/Sema/SemaDeclObjC.cpp
@@ -258,7 +258,8 @@
       S.Diag(ND->getLocation(), diag::note_method_declared_at)
         << ND->getDeclName();
     else
-      S.Diag(ND->getLocation(), diag::note_previous_decl) << "class";
+      S.Diag(ND->getLocation(), diag::note_previous_decl)
+          << (isa<ObjCCategoryDecl>(ND) ? "category" : "class");
   }
 }
 
@@ -1724,7 +1725,8 @@
                             Decl * const *ProtoRefs,
                             unsigned NumProtoRefs,
                             const SourceLocation *ProtoLocs,
-                            SourceLocation EndProtoLoc) {
+                            SourceLocation EndProtoLoc,
+                            AttributeList *AttrList) {
   ObjCCategoryDecl *CDecl;
   ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(ClassName, ClassLoc, true);
 
@@ -1801,6 +1803,9 @@
                                             NumProtoRefs, Context); 
   }
 
+  if (AttrList)
+    ProcessDeclAttributeList(TUScope, CDecl, AttrList);
+
   CheckObjCDeclScope(CDecl);
   return ActOnObjCContainerStartDefinition(CDecl);
 }
@@ -1865,9 +1870,10 @@
       CatIDecl->setImplementation(CDecl);
       // Warn on implementating category of deprecated class under 
       // -Wdeprecated-implementations flag.
-      DiagnoseObjCImplementedDeprecations(*this, 
-                                          dyn_cast<NamedDecl>(IDecl), 
-                                          CDecl->getLocation(), 2);
+      DiagnoseObjCImplementedDeprecations(
+          *this,
+          CatIDecl->isDeprecated() ? CatIDecl : dyn_cast<NamedDecl>(IDecl),
+          CDecl->getLocation(), 2);
     }
   }
 
Index: cfe/trunk/test/SemaObjC/attr-deprecated.m
===================================================================
--- cfe/trunk/test/SemaObjC/attr-deprecated.m
+++ cfe/trunk/test/SemaObjC/attr-deprecated.m
@@ -121,9 +121,15 @@
 }
 
 __attribute__((deprecated))
-@interface A(Blah) // expected-error{{attributes may not be specified on a category}}
+@interface A(Blah) // no warning
+- (A*)getA;
 @end
 
+@implementation A(Blah) // Don't warn by default
+- (A*)getA {
+  return self;
+}
+@end
 
 typedef struct {
 	int x;
Index: cfe/trunk/test/SemaObjC/category-attribute.m
===================================================================
--- cfe/trunk/test/SemaObjC/category-attribute.m
+++ cfe/trunk/test/SemaObjC/category-attribute.m
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fsyntax-only -ast-dump %s | FileCheck %s
+// expected-no-diagnostics
+
+__attribute__ ((external_source_symbol(language= "Swift", defined_in="A")))
+@interface TestInterface
+@end
+// CHECK: ObjCInterfaceDecl {{.*}} TestInterface
+// CHECK-NEXT: ExternalSourceSymbolAttr
+
+__attribute__ ((external_source_symbol(language= "Swift", defined_in="B")))
+@interface TestInterface ()
+@end
+// CHECK: ObjCCategoryDecl
+// CHECK-NEXT: ObjCInterface
+// CHECK-NEXT: ExternalSourceSymbolAttr {{.*}} "Swift" "B"
+
+__attribute__ ((external_source_symbol(language= "Swift", defined_in="C")))
+@interface TestInterface (Category)
+@end
+// CHECK: ObjCCategoryDecl
+// CHECK-NEXT: ObjCInterface
+// CHECK-NEXT: ExternalSourceSymbolAttr {{.*}} "Swift" "C"
Index: cfe/trunk/test/SemaObjC/default-synthesize-3.m
===================================================================
--- cfe/trunk/test/SemaObjC/default-synthesize-3.m
+++ cfe/trunk/test/SemaObjC/default-synthesize-3.m
@@ -33,8 +33,8 @@
 - (id) DeepMustSynthProperty { return 0; }
 @end
 
-__attribute ((objc_requires_property_definitions)) 
-@interface Deep(CAT)  // expected-error {{attributes may not be specified on a category}}
+__attribute ((objc_requires_property_definitions)) // expected-error {{'objc_requires_property_definitions' attribute only applies to Objective-C interfaces}}
+@interface Deep(CAT)
 @end
 
 __attribute ((objc_requires_property_definitions)) // expected-error {{'objc_requires_property_definitions' attribute only applies to Objective-C interfaces}}
Index: cfe/trunk/test/SemaObjC/warn-deprecated-implementations.m
===================================================================
--- cfe/trunk/test/SemaObjC/warn-deprecated-implementations.m
+++ cfe/trunk/test/SemaObjC/warn-deprecated-implementations.m
@@ -65,3 +65,10 @@
   return (void *)0;
 }
 @end
+
+__attribute__((deprecated))
+@interface Test(DeprecatedCategory) // expected-note {{category declared here}}
+@end
+
+@implementation Test(DeprecatedCategory) // expected-warning {{Implementing deprecated category}}
+@end